The present invention relates generally to the fabrication of components by the direct laser fusing of the material constituents. More particularly, the present invention has one form wherein the material constituents are directly melted by a laser and solidified to produce a high density part requiring little or no post processing. While, the present invention was developed for fabricating gas turbine engine components, certain applications may be outside of this field.
Since its inception in the 1930""s, the gas turbine engine has grown to be the workhorse power plant of modern aircraft. Over the years, there has been significant advances in the technology related to aircraft propulsion systems, and the methods of manufacturing these system components. Associated with the technological advances has been a desire to reduce engine life cycle costs by minimizing acquisition, operating, and maintenance costs. While there are many ways to reduce engine life cycle costs, one approach may be through technological developments such as advanced materials, innovative structural designs, improved aerothermodynamics, improved computational methods, and advanced manufacturing techniques.
Traditional manufacturing techniques have typically coupled the cost of manufacturing a part with the volume of parts produced. Manufacturing techniques that are designed for large scale production, such as casting and extrusion are often cost effective, but these manufacturing techniques are generally unacceptable for small quantities of parts. Another traditional manufacturing technique for producing parts is powder metallurgy which requires a tool for shaping the powder, therefore often rendering the powder metallurgy process unattractive for producing a limited quantity of parts.
Where only a small quantity of parts are desired, conventional subtractive machining method are often employed to produce the part. As is generally known to one familiar with manufacturing and machining processes, a conventional subtractive machining method utilizes the removal of a portion of the material from the initial block of material to produce the desired shape. Examples of conventional subtractive machining methods include: broaching, drilling, electric discharge machining, flame cutting, grinding, turning, etc. While the conventional subtractive machining methods are usually effective in producing the desired component, they have a multitude of limitations.
One limitation common to the conventional subtractive machining processes is the waste of a large amount of raw material. The conventional machining process usually involve an extensive setup to properly machine the part, and the setup and operation of the machine often relies a great deal on operator judgment and expertise. Another limitation associated with many conventional subtractive machining methods is the inaccuracies imparted into the manufacturing process due to machine and tooling wear. Further, an additional limitation of many conventional machining techniques relates to the difficulty of making certain part configurations. Therefore, there are certain configurations in which the part must be divided into segments for machining due to the inability of a cutting tool to produce the desired configuration.
There are other manufacturing processes which are additive in nature. The type of processes that would be classified as additive in nature include plating, cladding, flame spraying, welding, laminating, etc. However, these processes are generally used in conjunction with the conventional subtractive machining techniques to produce a component that cannot be directly machined.
Even with a variety of earlier methods and apparatus for manufacturing components, there remains a need for a method and apparatus for making components by direct laser processing. The present invention satisfies this need in a novel and unobvious way.
One embodiment of the present invention contemplates a an apparatus comprising a free form fabricated gas turbine component having a structure consistent with a metallurgical casting with a refined microstructure.
One object of the present invention is to provide a fabricated component for use in a gas turbine engine.
Related objects and advantages of the present invention will be apparent from the following description.